Micro-analysis chip, electrolyte concentration measuring system, and electrolyte concentration measuring method

Abstract

An object is to provide a micro-analysis chip in which a satisfactory area of contact between a specimen and an ion-selective membrane and an adequate amount of the specimen that reacts with the ion-selective membrane can be secured, and which is excellent both in measurement sensitivity and in ion selectivity. In order to achieve the object, a micro-analysis chip as described below is provided. That is, provided is a micro-analysis chip including a channel region which is surrounded by a channel wall provided inside a porous substrate. The channel region includes a first channel chamber containing a reference electrode, a second channel chamber containing a working electrode. The working electrode is covered with an ion-selective membrane containing an ingredient that has ion selectivity. The ion-selective membrane has an exposed surface serving as a dispensing section to which a specimen is dispensed.

What is claimed is: 
     
         1 . A micro-analysis chip comprising a channel region which is surrounded by a channel wall provided inside a porous substrate,
 wherein the channel region includes a first channel chamber, a second channel chamber, and a channel connecting the first channel chamber and the second channel chamber to each other,   wherein the first channel chamber includes a reference electrode, and the second channel chamber includes a working electrode,   wherein the working electrode is covered with an ion-selective membrane containing an ingredient that has ion selectivity, and   wherein the ion-selective membrane has an exposed surface serving as a dispensing section to which a specimen is dispensed.   
     
     
         2 . The micro-analysis chip according to  claim 1 , wherein, in the dispensing section, a height difference is created on the exposed surface of the ion-selective membrane between a central portion and a surrounding portion surrounding the central portion. 
     
     
         3 . The micro-analysis chip according to  claim 1 , wherein a surrounding of the dispensing section is covered with a regulation member impermeable by the specimen. 
     
     
         4 . The micro-analysis chip according to  claim 1 , further comprising a mark for positioning. 
     
     
         5 . An electrolyte concentration measuring system comprising:
 a micro-analysis chip;   a specimen supply unit configured to dispense a specimen to the micro-analysis chip; and   a measurement unit configured to measure a potential difference caused on the micro-analysis chip,   wherein the micro-analysis chip includes a channel region surrounded by a channel wall provided inside a porous substrate,   wherein the channel region includes a first channel chamber, a second channel chamber, and a channel connecting the first channel chamber and the second channel chamber to each other,   wherein the first channel chamber includes a reference electrode, and the second channel chamber includes a working electrode,   wherein the working electrode is covered with an ion-selective membrane containing an ingredient that has ion selectivity,   wherein the specimen supply unit is configured to supply the specimen so that at least a part of the specimen overlaps with an exposed surface of the ion-selective membrane covering the working electrode, and   wherein the measurement unit is configured to measure the potential difference between the reference electrode and the working electrode which reflects a difference in ion concentration.   
     
     
         6 . The electrolyte concentration measuring system according to  claim 5 , further comprising a positioning mechanism configured to determine relative positions between the specimen supply unit and the exposed surface of the ion-selective membrane. 
     
     
         7 . An electrolyte concentration measuring method using a micro-analysis chip,
 wherein the micro-analysis chip includes a channel region surrounded by a channel wall provided inside a porous substrate,   wherein the channel region includes a first channel chamber, a second channel chamber, and a channel connecting the first channel chamber and the second channel chamber to each other,   wherein the first channel chamber includes a reference electrode, and the second channel chamber includes a working electrode,   wherein the working electrode is covered with an ion-selective membrane containing an ingredient that has ion selectivity, and   the electrolyte concentration measuring method comprising:   dispensing a specimen so that at least a part of the specimen overlaps with an exposed surface of the ion-selective membrane covering the working electrode,   wherein an ion contained in the dispensed specimen and selected by the ion-selective membrane comes into contact with the working electrode,   wherein the dispensed specimen permeating the channel comes into contact with the reference electrode; and   measuring a potential difference between the reference electrode and the working electrode which reflects a difference in ion concentration.   
     
     
         8 . The electrolyte concentration measuring method according to  claim 7 , wherein the specimen is dispensed in a boundary portion between the ion-selective membrane and the porous substrate inside the second channel chamber.